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syslog-ng Premium Edition 6.0.21 - Administration Guide

Preface Chapter 1. Introduction to syslog-ng Chapter 2. The concepts of syslog-ng Chapter 3. Installing syslog-ng Chapter 4. The syslog-ng PE quick-start guide Chapter 5. The syslog-ng PE configuration file Chapter 6. Collecting log messages — sources and source drivers Chapter 7. Sending and storing log messages — destinations and destination drivers Chapter 8. Routing messages: log paths, reliability, and filters Chapter 9. Global options of syslog-ng PE Chapter 10. TLS-encrypted message transfer Chapter 12.  Reliable Log Transfer Protocol™ Chapter 13. Reliability and minimizing the loss of log messages Chapter 14. Manipulating messages Chapter 15. Parsing and segmenting structured messages Chapter 16. Processing message content with a pattern database Chapter 17. Statistics and metrics of syslog-ng Chapter 18. Multithreading and scaling in syslog-ng PE Chapter 19. Troubleshooting syslog-ng Chapter 20. Best practices and examples



pdbtool — An application to test and convert syslog-ng pattern database rules


pdbtool [command] [options]


This manual page is only an abstract, for the complete documentation of syslog-ng and pdbtool, the syslog-ng Documentation page.

The syslog-ng application can match the contents of the log messages to a database of predefined message patterns (also called patterndb). By comparing the messages to the known patterns, syslog-ng is able to identify the exact type of the messages, tag the messages, and sort them into message classes. The message classes can be used to classify the type of the event described in the log message. The functionality of the pattern database is similar to that of the logcheck project, but the syslog-ng approach is faster, scales better, and is much easier to maintain compared to the regular expressions of logcheck.

The pdbtool application is a utility that can be used to:

The dictionary command

dictionary [options]

Lists every name-value pair that can be set by the rules of the pattern database.

--dump-tags or -T

List the tags instead of the names of the name-value pairs.

--pdb <path-to-file> or -p <path-to-file>

Name of the pattern database file to use.

--program <programname> or -P <programname>

List only the name-value pairs that can be set for the messages of the specified $PROGRAM application.

The dump command

dump [options]

Display the RADIX tree built from the patterns. This shows how are the patterns represented in syslog-ng and it might also help to track down pattern-matching problems. The dump utility can dump the tree used for matching the PROGRAM or the MSG parts.

--debug or -d

Enable debug/diagnostic messages on stderr.

--pdb or -p

Name of the pattern database file to use.

--program or -P

Displays the RADIX tree built from the patterns belonging to the ${PROGRAM} application.

--program-tree or -T

Display the ${PROGRAM} tree.

--verbose or -v

Enable verbose messages on stderr.

Example and sample output:

pdbtool dump -p patterndb.xml  -P 'sshd'
   'assword for'
          'port '
            @NUMBER:@ rule_id='fc49054e-75fd-11dd-9bba-001e6806451b'
              ' ssh' rule_id='fc55cf86-75fd-11dd-9bba-001e6806451b'
                 '2' rule_id='fc4b7982-75fd-11dd-9bba-001e6806451b'
    'ublickey for'
           'port '
             @NUMBER:@ rule_id='fc4d377c-75fd-11dd-9bba-001e6806451b'
               ' ssh' rule_id='fc5441ac-75fd-11dd-9bba-001e6806451b'
                  '2' rule_id='fc44a9fe-75fd-11dd-9bba-001e6806451b'

The match command

match [options]

Use the match command to test the rules in a pattern database. The command tries to match the specified message against the patterns of the database, evaluates the parsers of the pattern, and also displays which part of the message was parsed successfully. The command returns with a 0 (success) or 1 (no match) return code and displays the following information:

  • the class assigned to the message (that is, system, violation, and so on),

  • the ID of the rule that matched the message, and

  • the values of the parsers (if there were parsers in the matching pattern).

The match command has the following options:

--color-out or -c

Color the terminal output to highlight the part of the message that was successfully parsed.

--debug or -d

Enable debug/diagnostic messages on stderr.

--debug-csv or -C

Print the debugging information returned by the --debug-pattern option as comma-separated values.

--debug-pattern or -D

Print debugging information about the pattern matching. See also the --debug-csv option.

--file=<filename-with-path> or -f

Process the messages of the specified log file with the pattern database. This option allows to classify messages offline, and to apply the pattern database to already existing logfiles. To read the messages from the standard input (stdin), specify a hyphen (-) character instead of a filename.

--filter=<filter-expression> or -F

Print only messages matching the specified syslog-ng filter expression.

--message or -M

The text of the log message to match (only the ${MESSAGE} part without the syslog headers).

--pdb or -p

Name of the pattern database file to use.

--program or -P

Name of the program to use, as contained in the ${PROGRAM} part of the syslog message.

--template=<template-expression> or -T

A syslog-ng template expression that is used to format the output messages.

--verbose or -v

Enable verbose messages on stderr.

Example: The following command checks if the patterndb.xml file recognizes the Accepted publickey for myuser from port 59357 ssh2 message:

pdbtool match -p patterndb.xml -P sshd -M "Accepted publickey for myuser from port 59357 ssh2"

The following example applies the sshd.pdb pattern database file to the log messages stored in the /var/log/messages file, and displays only the messages that received a useracct tag.

pdbtool match -p sshd.pdb \
  –file /var/log/messages \
  –filter ‘tags(“usracct”);’ 

The merge command

merge [options]

Use the merge command to combine separate pattern database files into a single file (pattern databases are usually stored in separate files per applications to simplify maintenance). If a file uses an older database format, it is automatically updated to the latest format (V3). See the syslog-ng Documentation page for details on the different pattern database versions.

--debug or -d

Enable debug/diagnostic messages on stderr.

--directory or -D

The directory that contains the pattern database XML files to be merged.

--glob or -G

Specify filenames to be merged using a glob pattern, for example, using wildcards. For details on glob patterns, see man glob. This pattern is applied only to the filenames, and not on directory names.

--pdb or -p

Name of the output pattern database file.

--recursive or -r

Merge files from subdirectories as well.

--verbose or -v

Enable verbose messages on stderr.


pdbtool merge --recursive --directory /home/me/mypatterns/  --pdb /var/lib/syslog-ng/patterndb.xml

Currently it is not possible to convert a file without merging, so if you only want to convert an older pattern database file to the latest format, you have to copy it into an empty directory.

The patternize command

patternize [options]

Automatically create a pattern database from a log file containing a large number of log messages. The resulting pattern database is printed to the standard output (stdout). The pdbtool patternize command uses a data clustering technique to find similar log messages and replacing the differing parts with @ESTRING:: @ parsers. For details on pattern databases and message parsers, see the syslog-ng Documentation page. The patternize command is available only in syslog-ng PE version 3.2 and later.

--debug or -d

Enable debug/diagnostic messages on stderr.

--file=<path> or -f

The logfile containing the log messages to create patterns from. To receive the log messages from the standard input (stdin), use -.

--iterate-outliers or -o

Recursively iterate on the log lines to cover as many log messages with patterns as possible.

--named-parsers or -n

The number of example log messages to include in the pattern database for every pattern. Default value: 1

--no-parse or -p

Do not parse the input file, treat every line as the message part of a log message.


Include a generated name in the parsers, for example, .dict.string1, .dict.string2, and so on.

--support=<number> or -S

A pattern is added to the output pattern database if at least the specified percentage of log messages from the input logfile match the pattern. For example, if the input logfile contains 1000 log messages and the --support=3.0 option is used, a pattern is created only if the pattern matches at least 3 percent of the log messages (that is, 30 log messages). If patternize does not create enough patterns, try to decrease the support value.

Default value: 4.0

--verbose or -v

Enable verbose messages on stderr.


pdbtool patternize --support=2.5 --file=/var/log/messages

The test command

test [options]

Use the test command to validate a pattern database XML file. Note that you must have the xmllint application installed. The test command is available only in syslog-ng PE version 3.2 and later.

--color-out or -c

Enable coloring in terminal output.

--debug or -d

Enable debug/diagnostic messages on stderr.

--debug or -D

Print debugging information on non-matching patterns.

--rule-id or -r

Test only the patterndb rule (specified by its rule id) against its example.


Validate a pattern database XML file.

--verbose or -v

Enable verbose messages on stderr.


pdbtool test --validate /home/me/mypatterndb.pdb




See also

The syslog-ng Documentation page




For the detailed documentation of syslog-ng PE see the syslog-ng Documentation page

If you experience any problems or need help with syslog-ng, visit the syslog-ng FAQ or the syslog-ng mailing list.

For news and notifications about of syslog-ng, visit the syslog-ng Blog.


This manual page was written by the One Identity Documentation Team <>.


Copyright© 2000-2018One Identity. Published under the Creative Commons Attribution-Noncommercial-No Derivative Works (by-nc-nd) 3.0 license. For details, see The latest version is always available at the syslog-ng Documentation page.

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